Sorry, we were out running hard making a little cash to pay the bills! The frame extension is steel, made to the same size/specs as the original frame. The wheels are American Racing AR-23 style 16" x 7" x 8 bolt 6.5" dia. bolt circle. It was very difficult to find a 7" wide wheel with the proper bolt holes/spacing, especially with enough weight rating. As long as it looks, there are many motorhomes with a lot more hanging off behind the axle!!! Of course, you won't find us loading 6,000 lbs right on the tail either, it has to be loaded properly!